Steam-engine



(No Model.) 4

11,11, WESTINGHOUSE & F. M. RITES.

STEAM ENGINE.

Patented Jan. 22,1889.

UNITED STATES PATENT GFFICEQ HENRY HERMAN \V INGHOUSE AND FRANCIS M.RITES, OF PITTSBURG,

PENNSYLVANIA.

STEAM-ENGINE.

SPECIFICATION forming part of Letters Patent No. 396,635, dated January22,, 1889.

Application filed October 31, 1888. Serial No. 289,637. (No model.)

To all whom it may concern:

Be it known that we, HENRY HERMAN WESTINGHOUSE and FRANCIS M. RrrEs,citizens of the United States, residing at Pitt.-

burg, in the county of Allegheny and State of Pennsylvania, haveinvented or discovered a certain new and useful Improvement inSteam-Engines, of which improvement the following is a specification.

Our present invention is an improvement upon that set forth in anapplication for Letters Patent filed by us March 17, 1888, Serial No.267,519, the essential characteristic of which consists in the provisionof a clearance-charm ber of such capacity as to admit of terminalhigh-pressure compression being raised to substantially initialpressure, and its object is to enable a compound engine embodying thesame to be readily and accurately adapted to the attainment of the aboveresult under and in accordance with variations in the character andconditions of the motive fluid employed in and the duty performed by theengine, without necessitating absolute accuracy in the originalproportionment of the clearance-chamber or involving any substantial orpermanent objection by reason 0t accidental or inadvertent departuretherefrom.

To this end our invention, generally stated, consists in thecombination, with the valvechest of a compound engine, of aclearancechamber of variable capacity, said chamber being interposedbetween the high and the low pressure cylinders and communicatingcontinuously with the high-pressure cylinder.

The improvement claimed hereinafter fully set forth.

The accompanying drawing is a longitudinal central section through thecylinders and valve-chest of a compound engine, illustrating theapplication of our invention.

The engine is shown as of the vesting house single-acting type, having ahigh-pressure cylinder, 1, and a low-pressure cylinder, 2, which aresecured side by side to the top of a crank-case, 5. The cylinders 1 and2 are fitted, respectively, with pistons 7 and S, which are coupled byconnecting rods 9, in. the usual manner, to crank-pins upon doublecranks on a suitable crank-shaft, which is fitted to rotate in bearingsin the lowerportion of the crank-case, and which, not being essential tothe explanation of our present invention, is not shown in the drawing.

The distribution functions of the engine are, as in our applicationbefore referred to,

effected by a single distributioirvalve, which reciprocates transverselyto the axes of the cylinders 1 2 in avalvechest, 3,which is secured toand forms the heads of the cylinders and is provided with nozzles orpassages 15 11, to which a steam and an exhaust pipe are re spectivelyconnected. The valve-chest 3,which is preferably lined with a bushing,40,communicates through ports 12 and 14. with the high and the lowpressure cylinders, ports corresponding with the ports 12 11 and withthe steam and exhaust passages being formed in the bushing 40. Thedistributionvalve is composed of a high-pressure section, 38, and alow-pressure section, 39*, connected by an intermediate body of smallerdiameter, so that an annular space shall bele'ft between the peripheryof the body and the valvechest bushing, and is fixed upon a valvestem,16, to which reciprocating movement is imparted by an eccentric on thecrankshaft, the eccentric-rod 19 being coupled to the Valve-stem by abell-crank lever, 4:5, and link 44. The valve-section 38 effectsadmission and cut-off for the high-pressure cylinder 1, and the section39 efl'ects admission, cut-off, compression, and exhaust for thelow-press ure cylinder 3 and exhaust and compression for thehigl'i-pressure cylinder. The setting and traverse of the valve are suchthat the higlrpressure port 12 shall be continuously open, and by theclosure of the low-pressure port 14 the valve coincidently initiateslowpressure expansion and high-pressure compression.

Our present invention is, similar to that set forth in our applicationbefore referred to, based upon our ascertainment by experi mentalresearch that a substantial advantage such volume as will permitcompression to be raised to, without exccedin g, initial pressure. Thecapacity of the clearance-chamber, while preferablybearing a ratio tothat of the highpressure cylinder substantially equivalent to the ratioof the high-pressure to the low-pressure cylinder, is not necessarilylimited to such ratio, and. differences in the character and conditionsof motive fluid and dutyin operation may render a greater or lessdeparture therefrom admissible or advisable. In order to permit of theaccurate adjustment of the volume of the clearance-chamber to adetermined and desired degree, which may not always be readily eitected.in the original construction of the engine, as well as to allow ofchanges in its yolume to be made from time to time, as may be founddesirable, we provide a clearan ce-chamber of variable capacity thevolume of which is capable of increase or diminution by ready andexpeditious hand adjustment whenever required.

The clearance-chamber .42, which .is herein illustrated, consists of atubular or cylindrical chamber of proper strength, which is socured tothe valvechest 3 in such position that its open lower end shall becontinuously in communication with the space within the Valve-chestbetween the end pistons, 38 39, of the valve, and consequently with thehighpressure port 12 and cylinder 1. The chamber 42 is closed to theatmosphere by an adjustable head or plate, 43, which is connected to thechamber in such manner that it maybe conveniently moved longitudinallyand fixed at any desired position therein. In this :instance theconnection of the head to the chamber and its adjustment therein areshown as effected by means of an external screw-thread on the headengaging a corresponding internal thread in the chamber, the head beingsuitably recessed on its outer face for the reception of awrenclnbywhich it is turned. It will be obvious that the chamber mightequivalently be bored out truly and the head he fitted to traversetherein, being provided with a threaded stem engaging a nut fixed to theouter end of the chamber, and that other modes of connection andadjustment which are within the knowledge of those skilled in the artmay be substituted, in the discretion of the constructor. As amechanical equivalent for an adjustable head, a plunger fitted totraverse longitudinally in the chamber an d passing through aproperly-packed stuffingbox thereon may be employed to effect desiredincrease or diminution of the volume of the chamber.

Our improvement enables any inaccuracy in. the original proportionmentof the clearance-chamber to a determined volume to be readily andcompletely corrected, as well as provides means for effecting suchvariation-in the volume of the chamber, without suspending or interferinwith the operation of the engine, as may under different conditions bedeemed necessary or advisable \Ve claim as our invention and desire tosecure by Letters Patent- 1. In a compound engine, the combination, sn l)stantiall y as set forth, of a valve-chest, a high-pressure cylindercon'lmunicating by a coi'itinuously-o pen port therewith, and aclearance-chamber of variable capacity which communicates continuouslywith the valve-chest and high-pressiwe-cylinder port.

2. In a compound engine, the combination, substantially as set forth, ofa valve-chest, a high-pressure cylinder communicating by acontinuously-open port therewith, a clearancechamber which communicatescontinuously with the valve-chest and l1igh-pressure-cylinder port, andan adjustable head or plunger adapted to traverse within and be fixed indifferent positions in the clearance-chamber.

In testimony whereof we have hereunto set our hands.

HENRY llERlllAN WES'llNGliOUSE. i 'LANCIS M. Itl'lES.

'Witnesses as to II. II. \Westinghouse:

R. W. BAYLEY, CHAs. P. LIVINGSTON. \Vitnesses as to F. M. Rites:

J. SNOWDEN BELL, R. H. WHITTLEsEY.

